Traditionally, in a heat pump, there has been known that presence of liquid refrigerant around a compressor at a time of starting the compressor may cause a damage to the compressor by the refrigerant. Further, in order to restrain this issue, there has been known such technology that a heater is provided to the compressor, and while a time taken before starting of electric conduction to the heater is made short in cases where the external air temperature at a time of stopping the compressor is low, the time taken before starting of electric conduction to the heater is made long or no electric conduction to the heater is performed in cases where the external temperature at the time of stopping the compressor is high (see for example PTL 1). This technology adjusts standby period until the electric conduction to the heater is started based on the external air temperatures, and therefore enables saving of electricity.